Quorum sensing Flashcards

1
Q

What is quorum sensing?

A
  • intercellular signalling (cell to cell communication)
  • sensing “like” cells
  • survey environment for like cells and share small specific molecules
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2
Q

What is triggered when a sufficient concentration of signalling molecule is present?

A
  • specific gene expression triggered
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3
Q

What is the advantage of quorum sensing?

A
  • ganging up
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4
Q

Where is QS carried out?

A
  • any prokaryote with regulatory pathway
  • gram neg
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5
Q

what does QS involve?

A
  • diffusible molecules of acylated homoserine lactone (AHL)
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6
Q

what happens when AHL is at sufficient concentrations?

A
  • induces activator proteins that trigger specific gene transcription
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7
Q

What causes light emission in bioluminescent organisms deep in the ocean?

A
  • vibrio fischeri
  • enzyme luciferase
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8
Q

What regulates lux operons when AHL levels are sufficient?

A
  • LuxR
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9
Q

What do QS systems control?

A
  • genes involved in pathogenesis of certain bacteria
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10
Q

What is a synergistic relationship?

A
  • bacteria gets nutrients, fish can see
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11
Q

What kind of bacteria is P. aeruginosa? What does it cause?

A
  • opportunistic
  • infections in lungs, skin and urinary tract
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12
Q

What activates virulence genes of p. aeruginosa? what activates the second subset of virulence genes?

A
  • LasI and LasR
  • Rhl system
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13
Q

What is Las system required for?

A
  • virulence of p aeruginosa and mature biofilm development
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14
Q

What does vibro cholerae do?

A
  • regulates biofilm formation and expression of virulence genes
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15
Q

What does QS of cholerae do to biofilm formation and virulence gene expression?

A
  • inhibits functions
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16
Q

biofilm formation and virulence gene expression are ______ at lower _____ _____.

A

higher at lower cell densities

17
Q

What is the proposed rationale of biofilm formation ?

A
  • inhibition of formation and toxin production at high cell densities promotes exit of bacteria from intestine and aids transmission
18
Q

What happens when there is a lot of vibrio cholerae?

A
  • increased concentration downregulates biofilm formation and exit
19
Q

What is the advantage of generation and emission outside of cell?

A
  • easier to attach and obtain nutrients
  • protected against environmental stressors
20
Q

What is a monoculture biofilm?

A
  • all same bacteria
    -ex. dental disease
21
Q

What is an environmental biofilm?

A
  • multiple bacteria
22
Q

What is successful biofilm formation associated with?

A
  • cell to cell signaling within bacterial populations
23
Q

What promotes survival strategies in biofilm?

A
  • enhanced opportunity for cooperative cell behaviour
  • depend on one another